Semaphorin

Semaphorins are a class of secreted and membrane proteins that were originally identified as axonal growth cone guidance molecules.

[1][2] Semaphorins are usually cues to deflect axons from inappropriate regions, especially important in the neural system development.

Every semaphorin is characterised by the expression of a specific region of about 500 amino acids called the sema domain.

Their discovery was in regards to axon guidance in the limb buds of grasshoppers in 1992, but since then, it has been discovered that semaphorins have a role in many processes.

Class 3 semaphorins modulate axonal regrowth, re-vascularisation, re-myelination and the immune response after central nervous system trauma.